JPS6025497B2 - Non-tempered high tensile strength steel plate with low yield ratio - Google Patents
Non-tempered high tensile strength steel plate with low yield ratioInfo
- Publication number
- JPS6025497B2 JPS6025497B2 JP2701279A JP2701279A JPS6025497B2 JP S6025497 B2 JPS6025497 B2 JP S6025497B2 JP 2701279 A JP2701279 A JP 2701279A JP 2701279 A JP2701279 A JP 2701279A JP S6025497 B2 JPS6025497 B2 JP S6025497B2
- Authority
- JP
- Japan
- Prior art keywords
- steel
- tensile strength
- yield ratio
- steel plate
- strength
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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- Heat Treatment Of Steel (AREA)
Description
【発明の詳細な説明】
この本発明は同一強度レベルの高張力鋼板に比して降状
比の低いポロン含有非調質高張力鋼板に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a poron-containing non-tempered high-strength steel plate that has a lower drop ratio than high-strength steel plates of the same strength level.
一般に降伏比の高い鋼は、伸びが4・さいために構造用
鋼として使用するとき、地震などに対して伸びが局部的
に集中して被断し易いために、土木建築の分野では歓迎
されない、そこで低降伏比鋼板としては抗張力80k9
/ゆで85%以下、抗張力70k9′微で80%以下、
また抗張力60k9′ゆで75%以下のものが望まれる
。In general, steel with a high yield ratio has a low elongation of 4. When used as structural steel, the elongation is locally concentrated and easily fractured due to earthquakes, etc., so it is not welcomed in the field of civil engineering and construction. Therefore, as a low yield ratio steel plate, the tensile strength is 80k9.
/ 85% or less when boiled, 80% or less when tensile strength is 70k9' fine,
Further, it is desired that the tensile strength is 60k9' and 75% or less when boiled.
また暁入、暁もどしの調質処理をせずに圧延のま)、ま
たは圧延後競ならし処理を行なう鋼にB(ポロン)を添
加することはきわめて稀で、優に英国におけるfort
iweld鋼が知られているのみである。In addition, it is extremely rare to add B (poron) to steel that is rolled without heat-refining or refining, or that is subjected to conditioning treatment after rolling.
Only iweld steel is known.
Bは鋼中に固溶し、オーステナィト粒界に偏折した状態
で嘘入性を高めるが、Nと結合してBNを生成すればそ
の焼入性を消失する。B dissolves in steel and improves hardenability when it is polarized at austenite grain boundaries, but when it combines with N to produce BN, the hardenability disappears.
そこでスラブ加熱時に固袴N量が多いと厚板圧延後の冷
却過程でBNを生成して、その後の工程におけるBの暁
入性向上効果がなくなる。たとえば、0.15%C−0
.25%Si−1.6%Mn−0.26%Mo−0.0
3%Nb−0.055%SoIN−0.001%Bを基
本成分としN含有量を異にしたA鋼とB鋼のスラブを1
250qoに加熱して圧延し、圧延のま)(放袷)の鋼
板×と、圧延後45000に3船ご保持して競もどし処
理した鋼板Yの抗張力TS、降伏点YS、降伏比YRを
調べた結果は図面に示すとおりであるが、N含有量の多
いA鋼の強度はN含有量の少し・B鋼に比べ低いことが
わかる。Therefore, if the amount of solid N is large when heating the slab, BN will be generated during the cooling process after rolling the thick plate, and the effect of improving the incorporation of B in the subsequent process will be lost. For example, 0.15%C-0
.. 25%Si-1.6%Mn-0.26%Mo-0.0
1 slab of A steel and B steel with 3%Nb-0.055%SoIN-0.001%B as the basic components and different N contents.
Examine the tensile strength TS, yield point YS, and yield ratio YR of steel plate X heated and rolled to 250 qo, unrolled (unrolled), and steel plate Y held in three ships at 45,000 qo after rolling and subjected to competitive treatment. The results are shown in the drawings, and it can be seen that the strength of Steel A, which has a high N content, is lower than that of Steel B, which has a small N content.
この発明は以上のように基いて、鋼中に含有するNを低
減することにより、鋼板圧延時にBの暁入性向上効果を
発揮させてアシキュラーベーナィト組織とし、調質処理
をせずして使用できる低降伏比の高張力鋼板を提案する
ものである。Based on the above, the present invention reduces the N content in steel, thereby exhibiting the effect of improving the permeability of B during rolling of a steel plate to form an acicular bainite structure, without the need for heat treatment. This paper proposes a high-strength steel plate with a low yield ratio that can be used in
すなち、この発明はCO.11〜0.35%、Sio.
05〜0.90%、Mno.75〜2.50%、Moo
.05%以上0.40%未満、Nbo.01〜0.08
%、Sol山0.03〜0.15%、BO.0002〜
0.0015%、残部Fe及び不可避的不純物よりなり
、不純物中のNを0.0035%以下とした低降伏比の
非調質高張力鋼板である。That is, this invention is CO. 11-0.35%, Sio.
05-0.90%, Mno. 75-2.50%, Moo
.. 05% or more and less than 0.40%, Nbo. 01-0.08
%, Sol mountain 0.03-0.15%, BO. 0002~
0.0015%, the balance being Fe and unavoidable impurities, and is a low yield ratio non-heat treated high tensile strength steel sheet with N in the impurities being 0.0035% or less.
この発明ではBとNが重要な構成要件であり、発明者は
種々試験の結果上記成分範囲の鋼板が降伏比が0.6以
下の非調質高張力鋼板としてすぐれた機械的性質を有す
ることを確認した。In this invention, B and N are important constituent elements, and as a result of various tests, the inventor has found that a steel plate with the above composition range has excellent mechanical properties as a non-heat treated high tensile strength steel plate with a yield ratio of 0.6 or less. It was confirmed.
つぎに、この発明鋼板の成分範囲を限定した理由につい
て述べる。Next, the reason for limiting the range of components of the steel sheet of this invention will be described.
Cは、高張力鋼としての強度を確保するために必要な元
素で、0.11%未満では機械的強度が得られない。C is an element necessary to ensure the strength of high-strength steel, and if it is less than 0.11%, mechanical strength cannot be obtained.
また0.35%をこえて含有すると溶接性を阻害するの
で0.11〜0.35%が適当である。Siは強度の確
保と製鋼上の必要性から0.05%未満にすることは好
ましくない。しかし0.90%をこえた含有は鞠性を大
中に劣化させる。Mnは0.75%未満では所望の強度
と戦性を得るのが困難になる。Moreover, if the content exceeds 0.35%, weldability will be inhibited, so a content of 0.11 to 0.35% is appropriate. It is not preferable for Si to be less than 0.05% from the viewpoint of ensuring strength and necessity for steel manufacturing. However, if the content exceeds 0.90%, the ballability deteriorates during the course. If Mn is less than 0.75%, it becomes difficult to obtain the desired strength and fighting properties.
また2.50%をこえた含有は異常組織を生起し、二枚
割れやラメラーティアの原因となり、溶接時にトラブル
を生じるので避くべきである。MoはBと共存したとき
暁ならし程度の遅い冷却速度での暁入性を高めるが0.
05%未満は効果がなく、また0.40%以上含有させ
てもそれ程の効果を生じない。Further, a content exceeding 2.50% should be avoided as it may cause an abnormal structure, causing splitting in two or lamellar tearing, and causing trouble during welding. When Mo coexists with B, it increases the dawning property at a cooling rate as slow as dawning, but 0.
If the content is less than 0.05%, there is no effect, and if the content is 0.40% or more, no significant effect will be produced.
Nbは0.01%以上の微量でも結晶粒を微細化し、低
温磁性を向上させるとともに、析出硬化によって強度を
上昇する。しかし0.08%をこえると溶接性を劣化さ
せる。SoIAIは低温瓢性向上のため0.03%以上
の含有量にするのが好ましい。Even in a trace amount of 0.01% or more, Nb refines crystal grains, improves low-temperature magnetism, and increases strength through precipitation hardening. However, if it exceeds 0.08%, weldability deteriorates. The content of SoIAI is preferably 0.03% or more in order to improve low-temperature melting properties.
しかし0.15%をこえると鋼塊割れの原因になるので
避けるべきである。Bは廉価で入手できる元素であり、
必要強度を非調質状態で確保するためにも、本発明の主
要な構成元素である。すなわち0.0002%以上の徴
量含有によって焼入‘性を高め強度を向上する。しかし
0.0015%をこえると籾性を劣化するので、その含
有量は0.0002〜0.0015%を適当とする。ま
たNの含有量はこの発明には極めて重要で、後記の実施
例からもわかるようにBN生成を抑制しBの糠入性を確
保するためその含有量を可及的少量に抑えるとともに、
後記実施例のように0.0035%以下にすべきである
。上記成分組成よりなる鋼板は、熱間圧延後通常の放冷
処理、すなわち圧延のま)でベイナイト組織を呈して良
好な強度と鋤性と、さらに同一強度の高張力鋼板より、
低い降伏比を示す。However, if it exceeds 0.15%, it should be avoided as it may cause cracking of the steel ingot. B is an element that can be obtained at a low price,
It is also a main constituent element of the present invention in order to ensure the necessary strength in a non-tempered state. That is, by containing 0.0002% or more of features, hardenability and strength are improved. However, if it exceeds 0.0015%, rice quality deteriorates, so the appropriate content is 0.0002 to 0.0015%. In addition, the content of N is extremely important for this invention, and as can be seen from the examples below, in order to suppress the formation of BN and ensure the branability of B, the content is kept as small as possible, and
It should be 0.0035% or less as shown in the examples below. The steel sheet having the above composition exhibits a bainitic structure after hot rolling and then normal cooling treatment (i.e., until rolling), and has good strength and plowability, and also has better strength and plowability than a high-tensile steel sheet with the same strength.
Shows low yield ratio.
しかし、より高劉性を得るためにさらに焼もどし処理を
加えることは任意である。つぎに、この発明鋼の実施例
について説明する。However, it is optional to further add tempering treatment to obtain higher strength. Next, examples of this invention steel will be described.
第1表に示すこの発明の成分鋼(A鋼、B鋼)とこの発
明に属さない比較鋼(C鋼、D鋼、E鋼)を溶製し、同
一条件で板厚15肋の厚板鋼板に熱間圧延後、それぞれ
圧延のま)のものと、45び0×0.批rの燐もどし処
理をしたものについて機械的試験をした。これらの結果
を第2表に示す。第1表 化学組成協
※ 戊酸当量はJIS G−3101に示す次式による
炭酸師=c+墨凶守十器十雫十*十台協第2表 試験結
果
上記より明らかなように、本発明鋼は比較鋼より低い炭
素当量で高い引張り強さを示し、また同程度の引張り強
さでは低い降伏比であることがわかる。The component steels of this invention shown in Table 1 (A steel, B steel) and comparative steels not belonging to this invention (C steel, D steel, E steel) were melted and made into thick plates with a thickness of 15 ribs under the same conditions. After hot-rolling the steel plate, and 45 and 0×0. A mechanical test was conducted on the material that had undergone phosphor reversion treatment. These results are shown in Table 2. Table 1: Chemical Composition Association* The boric acid equivalent is calculated according to the following formula shown in JIS G-3101: carbonic acid = c + Sumikyoshojukijushizukuju * Judaikyo Table 2 Test results As is clear from the above, the present invention It can be seen that the steel exhibits higher tensile strength at a lower carbon equivalent than the comparison steel, and also a lower yield ratio at the same tensile strength.
第1図はMo−Nb−B鋼におけるN含有量による抗張
力、降伏点、降伏比の比較図表である。FIG. 1 is a comparison chart of tensile strength, yield point, and yield ratio according to N content in Mo-Nb-B steel.
Claims (1)
90%、Mn0.75〜2.50%、Mo 0.05%
以上0.40%未満、Nb0.01〜0.08%、so
lAl 0.03〜0.15%、B 0.0002〜0
.0015%、残部Fe及び不可避的不純物よりなり、
不純物中のNが0.0035%以下であることを特徴と
する低降伏比の非調質高張力鋼板。1C 0.11-0.35%, Si 0.05-0.
90%, Mn 0.75-2.50%, Mo 0.05%
0.40% or more, Nb0.01-0.08%, so
lAl 0.03-0.15%, B 0.0002-0
.. 0015%, the balance consisting of Fe and unavoidable impurities,
A non-heat treated high tensile strength steel sheet with a low yield ratio, characterized in that N in impurities is 0.0035% or less.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2701279A JPS6025497B2 (en) | 1979-03-07 | 1979-03-07 | Non-tempered high tensile strength steel plate with low yield ratio |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2701279A JPS6025497B2 (en) | 1979-03-07 | 1979-03-07 | Non-tempered high tensile strength steel plate with low yield ratio |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS55119151A JPS55119151A (en) | 1980-09-12 |
JPS6025497B2 true JPS6025497B2 (en) | 1985-06-18 |
Family
ID=12209180
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2701279A Expired JPS6025497B2 (en) | 1979-03-07 | 1979-03-07 | Non-tempered high tensile strength steel plate with low yield ratio |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6025497B2 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0285336A (en) * | 1988-08-05 | 1990-03-26 | Nippon Steel Corp | Build-up and heat-resistant shape steel |
CN1039835C (en) * | 1995-07-20 | 1998-09-16 | 张玉田 | Non-hardened and non-tempered alloy structure steel and making process thereof |
-
1979
- 1979-03-07 JP JP2701279A patent/JPS6025497B2/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
JPS55119151A (en) | 1980-09-12 |
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